Accelerators for dry pipe sprinkler systems



Jan. 17, 1956 R. R. ROBBINS 2,731,091

ACCELERATORS FOR DRY PIPE SPRINKLER SYSTEMS Filed June 1, 1955 3 Sheets-Sheet l 2 hyve lyf'or El E Roberr R. Robbins Ac em- Jan. 17, 1956 R. R. ROBBINS 2,731,091

ACCELERATORS FOR DRY PIPE SPRINKLER SYSTEMS Filed June 1, 1953 5 Sheets-Sheet 2 {w AGENT Jan. 17. 1956 R. R. ROBBINS ACCELERATORS FOR DRY PIPE SPRINKLER SYSTEMS Filed June 1, 1953 AGENT United States Patent" ACCELERATORS FOR DRY PIPE SPRINKLER SYSTEMS Robert R. Robbins, Winnipeg, Manitoba, Canada Application June 1, 1953, Serial No. 358,819

Claims. (Cl. 169-17) The invention relates to fire sprinkler systems wherein multiple spaced pipe lines, having fusibly operable sprinkler units thereon, are connected to a water supply system through a dry pipe valve. In such systems, the dry pipe lines are under air pressure which, through suitable clappers in the dry pipe valve, hold back the water in the supply main until a sprinkler unit fuses, due to a fire occurring in the adjacent area. The compressed air in the dry pipe lines escapes through the fused unit until the pressure on the clappers drops sufficiently to be overcome by the water pressure thereagainst, and thereafter water is sprayed on the fire from the fused sprinkler unit.

It has been found that it takes from three to five minutes, after the sprinkler unit has fused, before the clappers will open under the above arrangement as the pressure drop is relatively slow and this time lag permits the fire to get considerable headway. tors have been designed to speed-up the clapper opening operation.

These accelerators usually consist of two chambers with a rubber diaphragm and a restricted passage therebetween. One chamber is connected direct to the dry pipe line so that changes in air pressure in both are simultaneous. Change of pressure in the second chamber however is retarded, due to the restricted passage. Accordingly, a sudden drop of air pressure in the dry pipe line will operate the diaphragm and, through suitable linkages, a valve is opened to neutralize the pressure on the air clapper in the dry pipe valve so that the water pressure against the water clapper can open both.

The difi'iculties experienced with such accelerators are: the rubber diaphragm deteriorates with time and ruptures when operated; foreign material from the dry pipe line enters the restricted passage, chokes same, and a gradual change in dry pipe line pressure will open the clappers; in some cases, the foreign material holds the restricting member open so the diaphragm cannot operate; the neutralizing valve corrodes and will not open, thus again resulting in failure of the accelerator.

The principal object of the present invention is to provide a ram-operable accelerator, idly movable by slow fluctuations of pressure in the dry pipe line, but operable by a sudden pressure drop therein to open a check valve to neutralize the air pressure on the air clapper for the quick opening of the dry pipe valve by water pressure.

A further object of the invention is to immerse the important Working parts of said accelerator in a permanent bath of oil to prevent deterioration or corroding of said parts and to maintain them well lubricated for efficient operation when required.

A further object of the invention is to construct the accelerator to automatically adjust itself to any required air pressure in the dry pipe line and still efliciently operate, as above described, upon a sudden pressure reduction therein.

A still further object of the invention is to utilize the Accordingly, accelera- I ram operation to release a latch for aresulting positive and powerful striker opening of the above mentioned neutralizing check valve.

I attain theabove important objects by providing a spring-loaded metal bellows in direct communication with the dry pipe line; operate a ram by the movement of the said bellows when the dry pipe line pressure varies; provide said ram with means for slow entrance or expulsion of the immersing oil thereto, when operated by slow changes of pressure, but adapted by a quick reduction of pressure to trip a latch for powerful spring ejection of a striker against and to positively open the neutralizing check valve. The details of the above construction will now be described, reference being had to the accompanying drawings in which:

Figure l is a perspective view of a sprinkler system, including the dry pipe valve, and showing the accelerator connected in the system.

Figure 2 is an enlarged vertical sectional view through the dry pipe valve.

Figure 3 is an enlarged vertical sectional view through the accelerator, the check valve, and the relief line.

Figure 4 is a vertical sectional view taken on the line 4-4, Figure 3.

Figure 5 is a vertical sectional View taken on the line 5-5, Figure 3.

Figure 6 is a horizontal sectional view taken on the line 66, Figure 3.

Figure 7 is a horizontal sectional view taken on the line 77, Figure 3.

Figure 8 is a partial vertical sectional view taken on the line 8S, Figure 3.

' Figure 9 is an enlarged perspective view of the catch shaft. Figure 10 is a perspective view of the re-setting tool.

In the drawings like characters of reference indicate corresponding parts in the several figures.

A standard sprinkler system is shown in perspective in Figure 1. This consists of a main water supply pipe 1 having water 2 therein under city pressure. This supply pipe is provided with a gate shut-off valve and a drain cock (both not shown) for shutting off the water from the system and for draining same. The supply pipe is connected to the lower part of a dry pipe valve 3 and a pipe 4 extends upwardly from this valve to a coupling 5 which in turn is connected by a pipe 6 with the lower part of a reducing T 7. A pipe 8 extends from the side of the T and connects with a header pipe 9 having a series of branch lines 19 extending therefrom, each branch line being provided with a plurality of spaced sprinkler units 11 therealong. As the construction and operation of such sprinkler units are well known they have not been detailed in the drawings. A further pipe extends from the upper part of the T 7 to supply sprinkler units of similar arrangement on upper floors but these have not been shown in the drawings. All pipes above the valve 3 are hereinafter referred to as the dry pipe line.

The dry pipe line valve 3 is generally shown in section in Figure 2 and comprises a casing 12. The supply pipe 1 connects with a seat 13 which is shown normally closed by a water clapper 14. This clapper is pivotally carried from an upper larger air clapper 15 which is pivoted within the casing at 16 and rests on a seat 17 formed in the casing. Restricted movement is permitted between the clappers by a pin and slot generally indicated at 18. A neutral chamber 19, between the two seats, can be drained of seepage water through a valve 234) and a pipe 21 is provided above the air clapper for compressed air entrance to the system.

Assuming that the sprinkler units are all shut and air under pressure has been pumped into the dry pipe line, itwill be seen that the pressure on the large air clapper will maintain the smaller water clapper closed to hold back the pressure of water 2 in the main pipe line. Should a fire occur and melt the fuse (not shown) of one of the sprinkler units 11, the unit will open, permit the air in the dry pipe line to bleed out and so reduce the pressure on the air clapper until the water pressure opens both clappers and they swing into the space .22 provided in the dry pipe valve 3. Accordingly, the Water flows through the dry pipe line and sprays out the fused sprinkler unit. As previously mentioned, this operation takes from three to five minutes and to speed-up the clapper opening, a relief line is added to the system. This relief line comprises a piping 23 connected from the coupling 5 to a T 24. The T is connected, through a check valve 25 and piping 26, with the neutral chamber 19 0f the dry pipe valve 3. When the check valve is opened, the air in the neutralizing chamber rises to approximately the same pressure as in the dry pipe line. As the water pressure behind the water clapper is always considerably higher than the air pressure, the water will now open both clappers and swing them into the area 22. The opening of the check valve is accomplished by an accelerator in combination with the connections therefrom to the relief line. New construction for this purpose constitutes my invention and will now be described.

The accelerator consists of a circular casing 27 having a drain plug 28 at the bottom thereof. The upper end of the casing is closed by a removable cover cap 29 which is held thereto by bolts 30, a suitable gasket being interposed. The cover cap is formed integral with a bail shaped open frame 31 having a central upper hole therein to receive a downwardly projecting nipple 32 of the check valve 25. A nut 33 screws on the nipple to secure and support the accelerator from the check valve.

The check valve comprises a pair of passageways 34 and 35, the passageway 34 connecting with the T 24 and the passageway 35 connecting with the piping 26. The passageways are connected within the check valve through a seat 36 which is normally closed by a sliding stem 37 mounted in a closure cap 38 at the top of the check valve. The cap is recessed to receive the upper end of a coil spring 39, the lower end of which resiliently presses against the stem 37 to hold it against the seat 36. A slidable striker pin 40 extends downwardly from just below the stem 37, through the nipple 32 and nut 33, and with the lower end terminating slightly below the nut. This striker pin is supported in the nut 33 by a pinned collar 41 thereon, the collar supporting packing 42 thereabove and within a chamber 43 in the nipple. When the striker pin is pushed up, the collar 41 will lift the packing to form a fluid-tight joint at the nipple bearing and prevent air escape from the check valve.

A tubing 44 is mounted Within the casing 27 of the accelerator. The upper end of the tubing is threaded, passes through a central hole in the cover cap .29 until an annular shoulder 45 thereon contacts the cap, and a nut 46 screws onto the threads against a gasket 47 to secure the tubing to the cap. A cross tubing 48 is formed integral with the tubing 44, below the shoulder 45, for a purpose later described. An annular flange 49 is formed integral with the tubing 44, below the cross tubing. A rectangular-shaped strap framework 50 is telescopically received centrally up the tubing 44 and the upper end is secured to the flange 49 by bolts 51. A boss 52 is carried by the upper end of this framework and encircles the tubing while the lower central part of the framework carries a downwardly extending boss 53 having a central tapped hole therein.

A circular, pleated bellows 54 is mounted within and rests upon the bottom of the framework 50, the interior being in communication with the tapped hole of the boss 53. The upper end of the bellows directly underlies and supports a flanged tubing 55 which slidably telescopes over the tubing 44. The flange of the tubing 55 is of U-shaped cross section to provide an annular, groove 56 therearound and a vent hole 57 extends from, this groove to the hollow centre of the tubing. A coil spring 58 encircles the tubing 55 with the upper end seated around the upper boss 52 and the'bottom end resting and pressing against the flange of the tubing 55. It will be seen that the coil spring 58 holds the bellows under compression. When the bellows expand upwardly, the resilience of this spring is increased,'while at the same time, the tubing 55 is raised until the upper end thereof contacts the boss 52.

A Y-shaped lever 59 has the forked ends thereof positioned within the frame 50 and pivoted thereon by side pins 60. The ends of the forks have inward pins 61 which ride in the groove .56 of the tubing 55. The lever is connected to the bottom of the framework 50 by a coil spring 59' to take up lost motion on the pins 60 and 61. The opposite end of the crank 59 projects from the frame 50 and pivotally receives one end of an upwardly projecting plunger 62 which telescopes into a downwardly projecting cylinder 63, thus forming a ram. The upper end of the cylinder is pivotally connected to one end of a lever 64. This latter lever is formed from strap material which passes by one side of the tubing 44, above the framework 50, is bent back on square corners and returns past the opposite side of the tubing. Both passing sides of the lever are pivoted to the tubing on pointed bolts 65 which screw through these side members of the lever with the pointed ends received in indents in the side of the tubing. Lock nuts 66, on the bolts, lock same in adjusted fulcruming position. The reversed portion of this crank has a central projecting pin 67 and a pair of steps 68 and 69 thereon, see Figure 8.

A catch shaft 70 (shown in Figure 9) is mounted in the cross tubing 48. One end of this shaft carries a washer 71 and a cotter pin 72 to prevent movement in one direction while the other end is pinned at 73 to a curved latch plate 74. The curved part of the latch plate has one end caught behind the step 68 of the lever 64 while the opposite end of the curve carries a projection 75 which is adapted, in the swinging of the latch plate, to contact the step 69, as a stop. A coil spring 76 has one end hooked onto the pin 67 While the upper end is hooked onto a pin 77 projecting from the latch plate, to resiliently hold the latch plate to the lever 64. A further pin 78 projects from the latch plate and is adapted to contact the side of the spring 76 and limit the turning movement of the latch plate in the opposite direction. The central part of the catch shaft 70 is filed half-way through, as at 79 (see Figure 9), to present a semicircular cross section at. this point and provide a catch. The cross tubing 48 is positioned on the tubing 44 such, that the centre of the catch shaft is just clear of the opening in the tubing 44.

A pin 80 passes across the bottom of the central tubing 44 to support a coil spring 81 therein. When the accelerator is set for operation, this coil spring is compressed by a push rod 82 which is pressed down from the upper end of the. tubing 44, but with the upper end still projecting slightly above the nut 46 and directly below the striker pin 40. This upper end is filed away on either side to provide a pair of ledges 83 for a purpose later described. The central part of the push rod 82 is grooved therearound at 84, and in the position shown in the drawings, this groove is directly opposite the filed catch 79. As the catch shaft has been turned, approximately one-half of this catch is overlying the groove 84 of the push rod to hold same against the resilience of the spring 81, the catch itself being held in position by the latch plate being caught behind the step 68.

From the above it will be seen that, when the lever 64 is operated to drop the step 68, against the resilience of the spring 76, the latchplate 74 will be released. Accordingly, the catch shaft and catch cannot hold the push rod against the spring 81. The push rod flies up under the resiliency of this spring, rotating the catch out of the way, and strikes the striker pin, which in turn strikes the stem 37 with far more than suflicient force to break any corrosion thereon and positively push up the stem against the resilience of the spring 39, to open the check valve, and hold it open. I

The lower boss 53 of the framework receives a fitting 85 in the central tapped hole. This fitting is connected, through a piping 86, with a double boss 87 formed in the cover cap 29 of the accelerator. The casing 27 is filled with oil 88 and this oil is inserted therein through a filler opening in the cover cap which is normally closed by a breather plug 89 having a dust cover 91 thereabove so the interior of the casing is under atmospheric pressure. It might be mentioned here that, when the ram is assembled, the cylinder 63, above the plunger 62, is preloaded with oil to prevent an air lock therein. A piping 91 connects the double boss 87 with a fitting 92 connected with the T 24 through a reducer 93. The fitting projects into the T and carries an interior tubular screen 94 having a chamber 95 therearound connecting with the interior of the T through a slot 96. The screen is inserted from the interior end of the fitting and is then sealed by a pressed-in plug 97.

All parts shown in the drawings are in position ready for sprinkler operation, it being understood that the sprinkler units are closed, the dry pipe line is under air pressure, and this air pressure has lifted the bellows and compressed the main coil spring 58. The clearance between the upper end of the tubing and the boss 52 permits a higher pressure if desired but contact of these parts is a safety factor to prevent stretching of the bellows beyond its capacity. Slight reduction or increase in air pressure over a time period will contract or expand the bellows and accordingly the ram (the plunger 62 and cylinder 63) will be operated slowly. In this slow operation, the immersing oil will slowly leak past the sides of the plunger, either exhausting from or entering the cylinder, but will not release the latch plate from the step 68. This same action occurs when the dry pipe line is being pumped up with compressed air as such pumping will be done while the spring 81 is positively held under pressure, as will later be described.

Should a tire occur, the sprinkler unit 11, adjacent the fire, will fuse and air will bleed therefrom, thus reducing the air pressure in the dry pipe line during the next few minutes. This pressure reduction will cause the bellows to contract, thus operating the lever 59. The pivot pins of this latter lever are so spaced that the plunger 62 of the ram will have considerable more movement than the bellows and this fast movement will cause the plunger to press on the oil in the cylinder 63 with considerable force, before it can escape past the plunger, and so operate the lever 64 against the resilience of the spring 76, to release the latch plate and permit the push rod and striker pin to open the check valve as above described. After releasing the latch plate, the upper end of the cylinder will strike a stop 63, formed as a web on the bottom of the cover plate 29. Any further movement of the plunger will force oil out of the cylinder, past the plunger. As the check valve is opened, the compressed air coming from the dry pipe line will enter the neutralizing chamber of the dry pipe valve 3. As the air pressure on both sides of the air clapper will be approximately the same, and the air pressure against the water clapper is lower than the water pressure on the other side of said clapper, both clappers will be swung open, water will pass up the dry pipe line and spray from the fused sprinkler unit. This water will also pass down the pipe lines 91 and 86 to expand the bellows, and again fill the ram cylinder with oil. When the main water pressure is shut-off by the gate valve (not shown), this pressure is released and the bellows again contracts and the ram operates, but the cylinder is again stopped by the stop 63.

Due to the hydraulic action of the ram, the latch plate is positively released, while the oil slippage past the ram plunger permits slow movement of the bellows to accominodate slight changes of pressure without releasing said latch plate. The release of the latch plate permits the spring 81 to exert its full force against the push rod, turn the catch 79 out of the road with ease, while the speed of the push rod against the striker pin and this pin against the stem 37 results in such a shock that any corrosion on or against the stem will be broken and the check valve must open, and stay open. As the packing 42 is lifted by the striker pin in this movement and is pressed tightly against the upper end of the chamber 43, no air can escape from the check valve. As all the essential parts of the accelerator are submerged in oil and provision is made for free movement of this oil right into the centre of the tubings as well as the ram, no jamming of such parts can occur, such as by rust, et cetera, and all are well lubricated for movement, even if a fire does not occur for years. There are no rubber diaphragms to deteriorate and rupture. Foreign material from the dry pipe line cannot enter the working parts, and is even prevented from entering the bellows and its piping by the screen 94, so cannot affect operation.

After the accelerator has been operated and the check valve opened, the mechanism can be re-set by the use of a re-setting tool shown at 98 in Figure 10. Assuming that the main supply pipe 1 has been shut off, the dry pipe line and the neutralizing chamber has been drained, this tool can be placed on the ledges 83 at the top of the push rod 82, as shown in dotted outline at 101 in Figure 3. The tool is provided with inturned spaced ridges 99 formed at the bottom of the U-bent walls 1%. The walls span the push rod and striker pin and as the tool is manually pushed inward, the upper curved edges 102 of the walls slide against the bottom of the nut 33, so that the push rod is again pressed down against the resilience of the spring 81. The dry pipe line is then pumped up with compressed air. This pressure will expand the bellows and lower the ram plunger. Accordingly, the lever 64 will move or swing until its turned-back end is contacting the latch plate as a stop. Thereafter, the plunger will move out of the cylinder, drawing oil therein. As the groove 84 of the push rod will be opposite the catch 79, the latch plate has been spring turned to the position shown in Figure 8 to catch behind the step 68. This turns the catch into the groove to cock the push rod. The resetting tool is then removed and the accelerator is ready for operation if another fire occurs.

This device could also be used to shut down machinery or create an alarm, not only in case of fire, but also if the ressure in an oil line were to suddenly drop. Many other uses would instantly occur to those working in many other types of work involving fluids under pressure or where variations in fluid pressures can be usefully employed.

What I claim as my invention is:

1. In a dry pipe sprinkler system having a dry pipe valve and an air pressured dry pipe line extending therefrom with fusible sprinkler units thereon; an accelerator for said system, comprising: a chamber in said dry pipe valve; a water clapper in said dry pipe valve for closing off a source of pressured water to said chamber; an air clapper between said chamber and said dry pipe line normally held closed by air pressure therefrom; said air clapper operably connected with said water clapper to normally hold said water clapper closed; a relief line from said dry pipe line to said chamber to neutralize the dry pipe line pressure on said air clapper for the opening oflease said push rod when a relative fast movement of said bellows occurs.

2. An accelerator for a dry pipe sprinkler system as defined in claim 1 wherein said push rod, bellows and linkage are contained Within a vented casing and submerged by oil therein for permanent lubrication of said parts.

3 In a fire sprinkler system having a dry pipe valve with interconnected normally seated double clappers therein, one clapper normally shutting off a source of water pressure by the action of the other clapper which is held normally shut by air pressure thereon from dry line having fusible sprinkler units thereon, and with a chamber between said clappers; means for accelerating the opening of said clappers, comprising: a relief line between said dry pipe line and said chamber to neutralize the dry pipe line air pressure on said other clapper; check valve in said relief line having a normally spring seated sliding stem shutting ofi said relief line; a bellows in fluid communication with said dry pipe line and operable by fluctuations of pressure therein; a resiliently loaded push rod operable to forcibly unseat said stern; a catch normally locking said push rod in said loaded position; linkage means connected between said catch and said bellows and operable thereby when a sudden pressure drop occurs in said dry pipe line to release said catch; a restricted lost motion member in said linkage means to permit a relatively slow movement of said bellows without releasing said catch; and said clappers adapted to open by said water pressure for passage of water through said dry pipe valve to said dry pipe line in the neutralizing of the pressure of said dry pipe line air pressure on the said other clapper.

4. In a fire sprinkler system having a dry pipe valve interconnected between a source of water pressure and an air pressured sprinkler carrying dry pipe line, and with a separate relief line between said dry pipe line and the neutralizing chamber of said dry pipe valve, for operation thereof; an accelerator for said operation, comprising: a check valve in said relief line normally closed by a resiliently seated stem therein; a casin adjacent said check valve; a spring loaded push rod carried by said casing and operable to forcibly open said seated stem; a catch holding said push red in said spring loaded position; a spring loaded bellows within said casing and having tie interior thereof in communication with said dry pipe line; a linkage between said catch and said bellows and operable thereby, in the fluctuations of air pressure in said dry pipe line, to release said catch; and a plunger and cylinder, having clearance therebetween, and forming a lost motion part of said linkage, to prevent the release of said catch in a relativeiy slow movement of said bellows.

5. An accelerator for a dry pipe sprinkler system as defined in claim 4 wherein said casing is vented and pro vided with means for filling same with and submerging said casing supporting working parts in oil.

References Cited in the file of this patent UNITED STATES PATENTS 2,022,671 Knight Dec. 3, 1935 2,047,719 Wallace .iuly 14, 1938 2,072,634 Grifiith Mar. 2, 1937 2,320,305 Rowley May 25, 1943 

